1. Field of the Invention
This Invention relates to an endoscope.
2. Description of the Prior Art
In a medical field, an endoscope is used for examination or diagnosis of an alimentary canal and the like. This endoscope includes an insertion section which is to be inserted into a body cavity and an operation section which is provided on the proximal end of the insertion section for operating the distal portion of the insertion section to bend it. Further, this endoscope also includes a connection section. The connection section extends from the operation section, and the free end thereof is to be connected to a light source device or a control device.
Since the endoscope is inserted into a body cavity having curved portions, the insertion section thereof includes a flexible tube which is flexible so as to be bendable along the curves of the body cavity and a bendable part provided on the tip part of the flexible tube so as to be bendable with operation of the operation section.
Inside the insertion section of such an endoscope, elongated members are arranged so as to pass through the interior space of the insertion section along the longitudinal direction as needed. Examples of the elongated members include a bending mechanism for bending the bendable part which is provided on the tip part of the insertion section; a light guide for transmitting illumination light emitted from a light source device to the distal end of the insertion section; an image guide for transmitting an observation image to the operation section, a forceps tube for inserting a forceps, used for performing a treatment, cytotechnology, or the like, into a body cavity; an air and/or liquid supply tube for supplying chemicals and the like into the body cavity; and the like.
In the endoscope having the above structure, when the flexible tube or the bendable part is bent, friction is produced among the respective elongated members provided in the interior space of the insertion section due to the bending operation, and as a result, pressure is exerted on the respective elongated members. In order to protect the respective elongated members from the friction and the pressure, a lubricant is usually provided around the respective elongated members.
However, since conventional lubricants do not have sufficient lubricity, there is a case that the elongated members, in particular, optical fibers constituting the light guide and the image guide are damaged or broken due to repeated bending operations.
Further, there are known some conventional lubricants having relatively high lubricity. However, even when such a lubricant is used, a relatively large amount of lubricant is required in order to obtain sufficient lubricity. When such a large amount of lubricant is used, there is a case that the lubricant is easily changed in quality and deteriorated due to sterilization of the endoscope, whereby resulting in the case that lubricity thereof is lowered or the endoscope is broken.